Experimental investigation of hydrodynamics and chromium(VI) adsorption in continuous countercurrent fluidized column

Continuous countercurrent fluidized column is fabricated to study the hydrodynamics and mass transfer of chromium(VI) ion from chromium aqueous solution to activated carbon. Hydrodynamics studies including pressure drop, holdup, and the flow pattern are studied. Batch adsorption studies are conducted to find the equilibrium time and effect of mass of adsorbent. Maximum percentage removal is obtained at maximum flow rates of water (1.42 cm/s) and solid particles (24.6 g/s) from the range of parameters studied in this work. For a given water velocity, the total pressure drop linearly increases along the length of the column because of the increase in frictional loss. Also, with an increase in water velocity, the solid holdup increases in the column. The percentage removal of chromium(VI) increased up to 60% along the length of the column because of the increased contact time between the adsorbent and the adsorbate. An empirical correlation is proposed to predict the solid holdup and mass transfer coefficient.